Welcome back! I reinstalled my copy a few days ago as well in order to start a Let's Play series on Youtube, and I can definitely agree it's difficult to get back into the swing of things.
If you have SH4 + the U-Boat Addon you should be using version 1.5, which to my knowledge is the most current version. If it's not 1.5 that's the patch you need to find, but I'm 98% sure that 1.5 is only attainable through a purchased copy of the U-Boat Missions add-on.
You have my apologies as I can't speak for Real Fleet Boat as I have never used it and have been running Trigger Maru Overhauled 2.5
As for the other suggested mods I know a lot of people really enjoy the Run Silent Run Deep campaign mod, and I did use it for a time, but I should mention it's for people who really know their history of the Pacific Theatre during WWII, as the traffic layer is extremely accurate down to the correct dates and times for convoys and task forces.
I am, unfortunately, not too up snuff on such things, so I've been running Trigger Maru by itself, albeit Ducimus has modded into that a very realistic traffic layer, just with a bit more of a chance to happen upon randoms. Provides a bit more action for people like me who don't know where to look for trouble.
So yes, I hope I helped some. I know there'll be skippers here with much better information than me when it comes to the correct version of RFB and some good mods to go with it.
Good luck, and welcome back!
